Financial Statements of Parent Company Guarantor - Condensed Consolidating Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Mar. 28, 2015	Dec. 31, 2014	Mar. 29, 2014	Dec. 31, 2013
Current assets
Cash and cash equivalents	$ 131.1	$ 110.4	$ 203.9	$ 256.0
Accounts and notes receivable, net	1,247.5	1,205.9
Inventories	1,177.0	1,130.4
Other current assets	412.5	366.8
Assets of Disposal Group, Including Discontinued Operation, Current	8.8	80.6
Total current assets	2,976.9	2,894.1
Property, plant and equipment, net	915.4	950.0
Other assets
Investments in subsidiaries		4,893.8
Goodwill	4,671.8	4,741.9
Intangibles, net	1,559.1	1,608.1
Other non-current assets	420.3	436.2
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	25.9	24.9
Total other assets	6,677.1	6,811.1
Total assets	10,569.4	10,655.2
Current liabilities
Current maturities of long-term debt and short-term borrowings	5.6	6.7
Accounts payable	504.9	583.1
Employee compensation and benefits	254.9	305.5
Other current liabilities	654.2	709.1
Liabilities of Disposal Group, Including Discontinued Operation, Current	11.5	35.1
Total current liabilities	1,431.1	1,639.5
Other liabilities
Long-term debt	3,403.4	2,997.4
Pension and other post-retirement compensation and benefits	300.9	322.0
Deferred tax liabilities	516.3	528.3
Other non-current liabilities	490.4	497.7
Liabilities of Disposal Group, Including Discontinued Operation, Noncurrent	4.0	6.5
Total liabilities	6,146.1	5,991.4
Equity
Shareholders' equity attributable to Pentair plc and subsidiaries	4,423.3	4,663.8
Total equity	4,423.3	4,663.8	5,936.3	6,217.7
Total liabilities and equity	10,569.4	10,655.2
Parent Company Guarantor
Current assets
Cash and cash equivalents	0	0	0.2	0.5
Accounts and notes receivable, net	0	0
Inventories		0
Other current assets	1.5	0
Total current assets	1.5	0
Property, plant and equipment, net		0
Other assets
Investments in subsidiaries	4,663.3	4,733.0
Other non-current assets	115.2	80.2
Total other assets	4,778.5	4,813.2
Total assets	4,780.0	4,813.2
Current liabilities
Current maturities of long-term debt and short-term borrowings		0
Accounts payable	0.3	0.9
Employee compensation and benefits	0.5	0.2
Other current liabilities	64.5	120.6
Total current liabilities	65.3	121.7
Other liabilities
Long-term debt	276.4	11.4
Other non-current liabilities	15.0	16.3
Total liabilities	356.7	149.4
Equity
Shareholders' equity attributable to Pentair plc and subsidiaries	4,423.3
Total equity		4,663.8
Total liabilities and equity	4,780.0	4,813.2
Guarantor Subsidiary [Member]
Current assets
Cash and cash equivalents	0
Accounts and notes receivable, net	0
Other current assets	15.7	17.6
Total current assets	15.7	17.6
Other assets
Investments in subsidiaries	4,825.1
Other non-current assets	0
Total other assets	4,825.1	4,893.8
Total assets	4,840.8	4,911.4
Current liabilities
Accounts payable	0
Employee compensation and benefits	0.1	0.6
Other current liabilities	1.6	2.2
Total current liabilities	1.7	2.8
Other liabilities
Long-term debt	175.8	175.6
Other non-current liabilities	0
Total liabilities	177.5	178.4
Equity
Shareholders' equity attributable to Pentair plc and subsidiaries	4,663.3
Total equity		4,733.0
Total liabilities and equity	4,840.8	4,911.4
Subsidiary Issuer
Current assets
Cash and cash equivalents	0.2	0.1	0.4	47.0
Accounts and notes receivable, net	0	0
Inventories		0
Other current assets	6.5	2.0
Total current assets	6.7	2.1
Property, plant and equipment, net		0
Other assets
Investments in subsidiaries	7,448.9	7,612.2
Other non-current assets	2,008.6	1,381.8
Total other assets	9,457.5	8,994.0
Total assets	9,464.2	8,996.1
Current liabilities
Current maturities of long-term debt and short-term borrowings		0
Accounts payable	0	0
Other current liabilities	13.3	10.9
Total current liabilities	13.3	10.9
Other liabilities
Long-term debt	3,267.1	2,860.6
Deferred tax liabilities	2.9	2.9
Total liabilities	3,283.3	2,874.4
Equity
Shareholders' equity attributable to Pentair plc and subsidiaries	6,180.9
Total equity		6,121.7
Total liabilities and equity	9,464.2	8,996.1
Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	130.9	110.3	203.3	208.5
Accounts and notes receivable, net	1,247.5	1,206.8
Inventories	1,177.0	1,130.4
Other current assets	416.5	367.6
Assets of Disposal Group, Including Discontinued Operation, Current	8.8	80.6
Total current assets	2,980.7	2,895.7
Property, plant and equipment, net	915.4	950.0
Other assets
Goodwill	4,671.8	4,741.9
Intangibles, net	1,559.1	1,608.1
Other non-current assets	294.7	345.0
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	25.9	24.9
Total other assets	6,551.5	6,719.9
Total assets	10,447.6	10,565.6
Current liabilities
Current maturities of long-term debt and short-term borrowings	5.6	6.7
Accounts payable	504.6	583.1
Employee compensation and benefits	254.3	304.7
Other current liabilities	602.5	595.8
Liabilities of Disposal Group, Including Discontinued Operation, Current	11.5	35.1
Total current liabilities	1,378.5	1,525.4
Other liabilities
Long-term debt	1,682.3	1,320.6
Pension and other post-retirement compensation and benefits	300.9	322.0
Deferred tax liabilities	513.4	525.4
Other non-current liabilities	475.4	481.4
Liabilities of Disposal Group, Including Discontinued Operation, Noncurrent	4.0	6.5
Total liabilities	4,354.5	4,181.3
Equity
Shareholders' equity attributable to Pentair plc and subsidiaries	6,093.1
Total equity		6,384.3
Total liabilities and equity	10,447.6	10,565.6
Eliminations
Current assets
Accounts and notes receivable, net	0	(0.9)
Other current assets	(27.7)	(20.4)
Total current assets	(27.7)	(21.3)
Other assets
Investments in subsidiaries	(16,937.3)	(17,239.0)
Other non-current assets	(1,998.2)	(1,370.8)
Total other assets	(18,935.5)	(18,609.8)
Total assets	(18,963.2)	(18,631.1)
Current liabilities
Accounts payable	0	(0.9)
Other current liabilities	(27.7)	(20.4)
Total current liabilities	(27.7)	(21.3)
Other liabilities
Long-term debt	(1,998.2)	(1,370.8)
Other non-current liabilities	0	0
Total liabilities	(2,025.9)	(1,392.1)
Equity
Shareholders' equity attributable to Pentair plc and subsidiaries	(16,937.3)
Total equity		(17,239.0)
Total liabilities and equity	$ (18,963.2)	$ (18,631.1)